Exhibit 99.1

FOR IMMEDIATE RELEASE NEWS RELEASE

Date Submitted:         April 23, 2007
NASDAQ Symbol:    FBMI Contact:   Samuel G. Stone
                  Executive Vice President and
                  Chief Financial Officer
                  (989) 466-7325

FIRSTBANK CORPORATION ANNOUNCES
FIRST QUARTER 2007 RESULTS

      Highlights Include:

• Earnings per share (diluted) up 10.8% to $0.41 for the first quarter of 2007 compared to $0.37 in the first quarter of 2006, benefiting from a favorable development in asset quality

• Net interest margin continues to contract due to the flat yield curve and increasing deposit costs

• Economic conditions limit growth opportunities

• Continued concentration on asset quality and expense control

• ICNB pending acquisition on track for 2nd quarter closing

Alma, Michigan (FBMI) — Thomas R. Sullivan, President and Chief Executive Officer of Firstbank Corporation, announced earnings per share of $0.41 for the first quarter of 2007, an increase of 10.8% compared to $0.37 for the first quarter of 2006. Net income was $2,658,000 for the quarter ended March 31, 2007, up 9.7% from the $2,424,000 for the quarter ended March 31, 2006. Returns on average assets and average equity for the first quarter of 2007 were 1.01% and 11.4%, respectively, compared with 0.96% and 10.8%, respectively, in the first quarter of 2006. Reversal of provision for loan loss expense due to the payoff of a credit with specific reserves was the primary reason for the improved financial results. Decline in the net interest margin and continued weak mortgage and real estate activity would have led to earnings and profitability measures weaker than the prior year were it not for the provision reversal. All per share amounts are fully diluted and have been adjusted to reflect the 5% stock dividend paid in December of 2006.

Firstbank recently received payoff on a loan relationship of approximately $4 million which has been discussed in previous disclosures. Although this loan was performing, a specific reserve had been established due to concerns regarding prospects for the business. The negative provision expense of $971,000 to reverse this specific reserve more than offset other positive expense posted in the quarter, resulting in a total provision for loan losses expense of negative $721,000 for the first quarter of 2007. The analysis of the allowance shows the resulting allowance as of March 31, 2007, of $9.1 million, or 1.00% of loans, to be appropriate.

Total portfolio loans of $913 million were 2.6% above the level at March 31, 2006. Total assets at March 31, 2007, were $1.1 billion and increased 4.2% over the year-ago period. Total deposits as of March 31, 2007, were $834 million, compared to $797 million at March 31, 2007, an increase of 4.6%.

Firstbank’s net interest margin, at 3.90% in the first quarter of 2007, declined by 8 basis points from the 3.98% level for the fourth quarter of 2006 and by 29 basis points from the 4.19% level in the first quarter of 2006. The continuing flat, and sometimes negatively sloped, yield curve continues to result in increasing funding costs relative to earning asset yields. Deposit balances continue to shift from non-interest bearing and lower rate products to higher rate products. Competitive pressures and the flat yield curve keep these deposit rates high providing only a narrow margin to rates available for making loans.

Mr. Sullivan stated, “Our industry continues to be under earnings strain, and for some banks there is a more serious problem of asset quality stress. These problems are particularly prevalent in Michigan, because plant closings and manufacturing job losses are having a direct and ripple effect on the economy. At Firstbank we know that above all else we must be careful stewards of asset quality, and I am pleased with the results our lenders have had in managing through a few difficult situations, and maintaining high quality underwriting and documentation standards. In the first quarter in particular, some of these efforts brought fruit in that we reversed a specific reserve because it was no longer needed and our non-performing and net charge-off ratios improved. We know that the economic stress in Michigan is not over, and we must continue the emphasis on asset quality. At the same time, we are working to contain expenses and trim non-productive expenses, because revenues are challenged by a weak real estate market and more pressure squeezing the spread between loan rates and deposit costs than we have ever before seen. We remain committed to serving our customers and communities well. We know that economies go through cycles, and when Michigan emerges from the current negative phase, we want our company and our position in our markets to be strong. We are looking forward to the expansion of our service area into the communities covered by ICNB, and we believe this acquisition will help position our company more strongly for the future.”

In the first quarter of 2007, Firstbank realized $130,000 in losses on sale of securities from the investment portfolio as advantage was taken of market opportunities to improve yields going forward. A partial offset to this loss was a gain on a sale of an other real estate owned property. Non-interest income showed small declines from prior quarter and year ago and would have shown small increases without the negative impact of the loss on security sales. Revenue from gain on sale of mortgages and real estate activity continued to be weak.

In the first quarter of 2007, non-interest expense was reduced by 3.6% from the fourth quarter of 2006. Even with three additional branch offices in operation compared to year-ago, non-interest expense in the first quarter of 2007 was held to 2.4% above the level in the first quarter of 2006. As revenues continue under pressure from the narrowing net interest margin and weak mortgage activity, Firstbank continues to work to contain expenses and where possible to trim non-productive expenses. Expenses in all non-bank subsidiaries have been scaled back.

Net charge-offs were $164,000 in the first quarter of 2007. Excluding the negative component of provision expense of $971,000 discussed above, provision expense exceeded net charge-offs. Annualized as a percentage of average loans, net charge-offs were 0.07% in the first quarter of 2007. The ratio of non-performing loans (including loans past due over 90 days) to loans was 0.34% at March 31, 2007, showing significant improvement from 0.47% at December 31, 2006, and 0.72% at March 31, 2006.

Shareholders’ equity increased 2.1% in the first quarter of 2007, and was 3.8% above the level at March 31, 2006. The ratio of average equity to average assets stood at 8.9% in the first quarter of 2007 – a level consistent over the past two years – indicating that strong equity capital has been maintained. Firstbank did not repurchase shares in the first quarter of 2007, as it expects to achieve increased leverage of its capital base to an appropriate level through the structure of the pending acquisition of the $236 million asset ICNB Financial Corporation. The purchase is being accomplished with a mix of 50% Firstbank Corporation stock and 50% cash, and Firstbank anticipates issuing additional trust preferred through a pooling arrangement in connection with this transaction. The merger transaction is expected to close at the end of the second quarter of 2007.

Firstbank Corporation, headquartered in Alma, Michigan, is a six bank financial services company with assets of $1.1 billion and 41 banking offices serving Michigan’s Lower Peninsula. Bank subsidiaries include: Firstbank – Alma; Firstbank (Mt. Pleasant); Firstbank – West Branch; Firstbank – Lakeview; Firstbank – St. Johns; and Keystone Community Bank.

This press release contains certain forward-looking statements that involve risks and uncertainties. When used in this press release the words “anticipate,” “believe,” “expect,” “hopeful,” “potential,” “should,” and similar expressions identify forward-looking statements. Forward-looking statements include, but are not limited to, statements concerning future business growth, changes in interest rates, and the resolution of problem loans. Such statements are subject to certain risks and uncertainties which could cause actual results to differ materially from those expressed or implied by such forward-looking statements, including, but not limited to, economic, competitive, governmental and technological factors affecting the Company’s operations, markets, products, services, interest rates and feefvs for services. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release.

FIRSTBANK CORPORATION
CONSOLIDATED BALANCE SHEETS
(Dollars in thousands)
UNAUDITED

	Mar 31 2007			Dec 31 2006			Mar 31 2006
ASSETS
Cash and cash equivalents:
Cash and due from banks	$	28,091		$	32,084		$	26,382
Short term investments		32,739			24,853			8,383
Total cash and cash equivalents		60,830			56,937			34,765
Securities available for sale		68,651			69,125			75,526
Federal Home Loan Bank stock		5,924			5,924			6,506
Loans:
Loans held for sale		283			1,120			1,167
Portfolio loans:
Commercial		199,067			194,810			188,516
Commercial real estate		266,084			286,249			300,858
Residential mortgage		295,385			284,137			275,190
Real estate construction		89,844			81,218			65,768
Consumer		62,201			63,106			59,380
Total portfolio loans		912,581			909,520			889,712
Less allowance for loan losses		(9,081	)		(9,966	)		(11,562	)
Net portfolio loans		903,500			899,554			878,150
Premises and equipment, net		20,251			20,232			19,468
Goodwill		20,094			20,094			19,888
Other intangibles		2,884			3,045			3,542
Other assets		18,684			19,061			17,803
TOTAL ASSETS	$	1,101,101		$	1,095,092		$	1,056,815
LIABILITIES AND SHAREHOLDERS' EQUITY
LIABILITIES
Deposits:
Noninterest bearing accounts	$	120,295		$	131,942		$	123,145
Interest bearing accounts:
Demand		167,082			161,228			175,866
Savings		134,484			127,301			132,491
Time		359,556			350,710			300,673
Wholesale CD's		52,195			64,245			65,077
Total deposits		833,612			835,426			797,252
Securities sold under agreements to
repurchase and overnight borrowings		38,170			35,179			39,006
FHLB Advances and notes payable		94,146			94,177			91,838
Subordinated Debt		20,620			20,620			20,620
Accrued interest and other liabilities		16,423			13,617			13,528
Total liabilities		1,002,971			999,019			962,244
SHAREHOLDERS' EQUITY
Preferred stock; no par value, 300,000
shares authorized, none issued
Common stock; 20,000,000 shares authorized		92,373			91,652			87,711
Retained earnings		5,749			4,552			7,239
Accumulated other comprehensive income/(loss)		8			(131	)		(379	)
Total shareholders' equity		98,130			96,073			94,571
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$	1,101,101		$	1,095,092		$	1,056,815
Common stock shares issued and outstanding		6,518,143			6,484,202			6,595,628
Principal Balance of Loans Serviced for Others ($mil)	$	470.5		$	472.0		$	471.8
Asset Quality Ratios:
Non-Performing Loans / Loans^		0.34	%		0.47	%		0.72	%
Non-Perf. Loans + OREO / Loans^ + OREO		0.48	%		0.65	%		0.86	%
Non-Performing Assets / Total Assets		0.40	%		0.54	%		0.72	%
Allowance for Loan Loss as a % of Loans^		1.00	%		1.10	%		1.30	%
Allowance / Non-Performing Loans		293	%		234	%		180	%
Quarterly Average Balances:
Total Portfolio Loans^	$	903,807		$	915,191		$	883,598
Total Earning Assets		990,838			999,225			974,534
Total Shareholders' Equity		96,590			95,761			93,772
Total Assets		1,087,428			1,083,518			1,054,024
Diluted Shares Outstanding		6,516,568			6,543,831			6,629,428

^ Total Loans less loans held for sale

FIRSTBANK CORPORATION
CONSOLIDATED STATEMENTS OF INCOME
(Dollars in thousands except per share data)
UNAUDITED

	Three Months Ended:
	Mar 31 2007			Dec 31 2006			Mar 31 2006
Interest income:
Interest and fees on loans	$	16,798		$	17,303		$	15,843
Investment securities
Taxable		626			534			513
Exempt from federal income tax		270			266			248
Short term investments		311			150			111
Total interest income		18,005			18,253			16,715
Interest expense:
Deposits		6,507			6,469			4,944
Notes payable and other borrowing		1,977			1,992			1,829
Total interest expense		8,484			8,461			6,773
Net interest income		9,521			9,792			9,942
Provision for loan losses		(721	)		169			185
Net interest income after provision for loan losses		10,242			9,623			9,757
Noninterest income:
Gain on sale of mortgage loans		324			309			248
Service charges on deposit accounts		944			935			922
Gain (loss) on sale of securities		(130	)		0			6
Mortgage servicing		145			194			84
Other		949			930			1,023
Total noninterest income		2,232			2,368			2,283
Noninterest expense:
Salaries and employee benefits		4,730			4,817			4,558
Occupancy and equipment		1,351			1,339			1,272
Amortization of intangibles		161			161			168
FDIC insurance premium		24			25			28
Other		2,429			2,677			2,466
Total noninterest expense		8,695			9,019			8,492
Income before federal income taxes		3,779			2,972			3,548
Federal income taxes		1,121			804			1,124
Net Income	$	2,658		$	2,168		$	2,424
Fully Tax Equivalent Net Interest Income	$	9,698		$	9,971		$	10,084
Per Share Data:
Basic Earnings	$	0.41		$	0.33		$	0.37
Diluted Earnings	$	0.41		$	0.33		$	0.37
Dividends Paid	$	0.225		$	0.214		$	0.210
Performance Ratios:
Return on Average Assets*		1.01	%		0.79	%		0.96	%
Return on Average Equity*		11.4	%		8.9	%		10.8	%
Net Interest Margin (FTE) *		3.90	%		3.98	%		4.19	%
Book Value Per Share+	$	15.05		$	14.82		$	14.33
Average Equity/Average Assets		8.9	%		8.8	%		8.9	%
Net Charge-offs	$	164		$	892		$	182
Net Charge-offs as a % of Average Loans^*		0.07	%		0.39	%		0.08	%

* Annualized
+ Period End
^ Total loans less loans held for sale